Scientists can grow a new ear within days by using 3D computer printers that
could in an advance that could be used in humans within three years, it has
been claimed.

The artificial ear could be used for patients who have suffered accidents or assaults and for the hundreds of children born each year missing one or both natural ears.

At present the only reliable method is to take a piece of rib bone and carve and mold it into an ear shape before covering it with skin grafts.

Scientists in New York hope that the new technique will be less invasive for the patient and look more natural.

Bioengineers at Cornell Medical College devised a method using 3D computer images of the ear and created collagen molds to form a scaffold which was then covered with cells taken from a calf's ear. They were grown in the laboratory before being implanted under the skin of rats.

It was found that the ears grew their own cartilage which was 'robust' three months after implantation in the rats.

It is hoped the technique can be used in humans within three years, they said.

The findings were published in the journal Public Library of Science One.

Co-author Lawrence Bonassar, associate professor of biomedical engineering, said: "This is such a win-win for both medicine and basic science, demonstrating what we can achieve when we work together.

"It takes half a day to design the mold, a day or so to print it, 30 minutes to inject the gel, and we can remove the ear 15 minutes later. We trim the ear and then let it culture for several days in nourishing cell culture media before it is implanted."

Co-author Dr Jason Spector, director of the Laboratory for Bioregenerative Medicine and Surgery and associate professor of plastic surgery at Weill Cornell in New York City said: "A bioengineered ear replacement like this would also help individuals who have lost part or all of their external ear in an accident or from cancer."

He added that the best time to implant a bioengineered ear on a child would be when they are about five or six-years-old. At that age, ears are 80 per cent of their adult size, he said.

Other teams around the world are working on similar techniques.

A variety of human parts have already been constructed in the laboratory and implanted in humans.

Scientists have made windpipes, bladders and miniaturised livers.

The 3D printing technique has also been used to make one-off replacement body parts including a jaw bone.

Mr David Gagult, an ear reconstruction surgeon at the Portland private hospital in central London said surgery is moving on at a rapid pace and bioengineering was playing an increasing role in that.

"This is an interesting step forward and if it works in humans may mean we no longer have to use rib from the patient, making it less invasive for them, or plastic scaffolds which can have complications."

However he warned that the team had found a novel way of producing a biological ear scaffold the problem will come when it needs to be inserted into the tight skin of the head. He said the skin on the back of the rat was baggy and so the skin covering was easy.

If the scaffold is not strong enough it would collapse when inserted, he said.

The team also need to overcome problems with rejection which could be done if the patients own cells were used instead of calf cells, he said.

Prof Neil Hopkinson, Professor of Manufacturing Engineering at Sheffield University, said the team had been sensible to use 3D printing techniques to create the mold for the ear but were a long way from the 'holy grail' which would be to print an ear directly without the need for a mold.